Introduction

In this project, we perform in-depth EDA(Exploratory Data Analysis) on a collection of data sets about COVID-19 in South Korea. Our goal is to use these data to better understand COVID and learn how to prevent it effectively to save lives.

Library Dependencies

Our project utilizes the following libraries, please make sure they are installed by using the install.packages() command.

Datasets

The data is collected from KCDC (Korea Centers for Disease Control & Prevention). The data set is available on Kaggle.

# Read Datasets, treat empty string value as NA
case <- read.csv('./Data/Case.csv', na.strings = c("", "NA"))
patient <- read.csv('./Data/PatientInfo.csv', na.strings = c("", "NA"))
policy <- read.csv('./Data/Policy.csv', na.strings = c("", "NA"))
region <- read.csv('./Data/Region.csv', na.strings = c("", "NA"))
searchtrend <- read.csv('./Data/SearchTrend.csv', na.strings = c("", "NA"))
seoulfloating <- read.csv('./Data/SeoulFloating.csv', na.strings = c("", "NA"))
time <- read.csv('./Data/Time.csv', na.strings = c("", "NA"))
timeage <- read.csv('./Data/TimeAge.csv', na.strings = c("", "NA"))
timegender <- read.csv('./Data/TimeGender.csv', na.strings = c("", "NA"))
timeprovince <- read.csv('./Data/TimeProvince.csv', na.strings = c("", "NA"))
weather <- read.csv('./Data/Weather.csv', na.strings = c("", "NA"))
route <- read.csv('./Data/routes.csv', na.strings = c("", "NA"))
patient_1 <- read.csv('./Data/patients.csv', na.strings = c("", "NA"))

Explotary Data Analysis (EDA)

This section contains our analysis of the data in many directions by using visualization.

Load Libraries

library(tidyverse)
## ── Attaching packages ─────────────────────────────────────── tidyverse 1.3.1 ──
## ✓ ggplot2 3.3.3     ✓ purrr   0.3.4
## ✓ tibble  3.1.2     ✓ dplyr   1.0.6
## ✓ tidyr   1.1.3     ✓ stringr 1.4.0
## ✓ readr   1.4.0     ✓ forcats 0.5.1
## ── Conflicts ────────────────────────────────────────── tidyverse_conflicts() ──
## x dplyr::filter() masks stats::filter()
## x dplyr::lag()    masks stats::lag()
library(ggplot2)
library(ggmap)
## Google's Terms of Service: https://cloud.google.com/maps-platform/terms/.
## Please cite ggmap if you use it! See citation("ggmap") for details.
library(gganimate)

library(tibbletime)
## 
## Attaching package: 'tibbletime'
## The following object is masked from 'package:stats':
## 
##     filter
library(data.table)
## 
## Attaching package: 'data.table'
## The following objects are masked from 'package:dplyr':
## 
##     between, first, last
## The following object is masked from 'package:purrr':
## 
##     transpose
library(htmltools)
library(leaflet)
library(htmlwidgets)

Total Confirmed Cases by Dates

# Filter out empty value for confirmed date
patient_dates <- patient_1 %>% 
  filter(!is.na(confirmed_date))

# Plot confirmed cases for each day
patient_dates %>%
  group_by(confirmed_date) %>%
  summarise(n = n()) %>%
  ggplot(aes(as.Date(confirmed_date, format = "%m/%d/%Y"), n))+
  geom_line(size = 2, alpha = 0.8, col="red")+
  geom_point(size = 5, alpha = 1, col="purple")+
  labs(title = "Confirmed Cases of COVID-19 in South Korea by Date",
       subtitle = paste0("Total Confirmed Cases: ", nrow(patient)),
       caption = "Green Line Indicates the Trend") + 
  scale_x_date(date_labels = "%b %d", date_breaks = "2 days") +
  theme_light() +
  theme(plot.title = element_text(face = "bold", 
                                  hjust = 0.5, size = 18, color = "black"),
        plot.subtitle = element_text(face = "bold", 
                                     size = 12, color = "blue")) +
  ggrepel::geom_label_repel(aes(label=n), hjust=1.5, vjust=0.9, 
                            fill ="orange") +
  geom_smooth(method = "gam", se = TRUE, alpha = 0.5, col = "green")

Confirmed Cases Among Different Age Groups

# Calculate Age for each Confirmed Case
patient_age <- patient_1
patient_age$age = 2020 - patient_1$birth_year

# Calculate Age Groups for Confirmed Cases by 10
patient_age$age_group = cut(patient_age$age,
                        breaks = seq(0,90, by=10),
                        right = FALSE,
                        labels = c("0-10","10-20","20-30",
                                   "30-40","40-50","50-60",
                                   "60-70","70-80","80-90"))

patient_age <- patient_age %>%
    select(age_group) %>%
    na.omit() %>%
    group_by(age_group) %>%
    summarise(confirmed_cases = n())
  
ggplot(patient_age, aes(y = age_group, x = confirmed_cases, fill = age_group)) +
  geom_bar(stat="identity") +
  xlab("Confirmed Cases") +
  ylab("Age Group") +
  ggtitle(label = "Confirmed Cases by Age Group")

Deceased Cases Among Different Age Groups

# Calculate Age for each Confirmed Case
patient_age <- patient_1
patient_age$age = 2020 - patient_1$birth_year

# Calculate Age Groups for Confirmed Cases by 10
patient_age$age_group = cut(patient_age$age,
                            breaks = seq(0,90, by=10),
                            right = FALSE,
                            labels = c("0-10","10-20","20-30",
                                       "30-40","40-50","50-60",
                                       "60-70","70-80","80-90"))
patient_age = patient_age[!is.na(patient_age$deceased_date),]

patient_age <- patient_age %>%
  select(age_group) %>%
  na.omit() %>%
  group_by(age_group) %>%
  summarise(deceased_cases = n())

ggplot(patient_age, aes(y = age_group, x = deceased_cases, fill = age_group)) +
  geom_bar(stat="identity") +
  xlab("deceased Cases") +
  ylab("Age Group") +
  ggtitle(label = "Deceased Cases by Age Group")

Province with the Highest Number of Confirmed Cases

# Group number of patients by province
patient_province <- patient
patient_province <- patient_province %>%
  select(province) %>%
  na.omit()%>%
  group_by(province)%>%
  summarise(n=n())

ggplot(patient_province, aes(y=n, x=reorder(province,n), fill=province)) +
    geom_bar(stat="identity") +
    coord_flip() +
    xlab("Province Name") +
    ylab("Confirmed Cases") +
    ggtitle(label = "Confirmed Cases in Each Province")

Confirmed Cases among Genders

patient_gender <- patient
patient_gender <- patient_gender %>%
  select(sex) %>%
  na.omit() %>%
  group_by(sex) %>%
  summarise(patient_num = n())

ggplot(patient_gender,
       aes(x="",y=patient_num,fill=sex)) + 
  geom_bar(width=1, stat="identity",color="white") + 
  ggtitle(label = "Confirmed Cases Gender Ratio in South Korea") + 
  coord_polar("y",start=0) + 
  geom_text(aes(label=paste0(round(patient_num/ sum(patient_num)*100,1),"%")),
            position=position_stack(vjust=0.5)) + 
  theme_void() + 
  theme(plot.title = element_text(size = 30, face = "bold"))

Deceased Cases among Genders

patient_gender <- patient
patient_gender = patient_gender[!is.na(patient_gender$deceased_date),]
patient_gender <- patient_gender %>%
  select(sex) %>%
  na.omit() %>%
  group_by(sex) %>%
  summarise(patient_num = n())
ggplot(patient_gender,
       aes(x="",y=patient_num,fill=sex)) + 
  geom_bar(width=1, stat="identity",color="white") + 
  ggtitle(label = "Deceased Gender Ratio in South Korea") + 
  coord_polar("y",start=0) + 
  geom_text(aes(label=paste0(round(patient_num/ sum(patient_num)*100,1),"%")),
            position=position_stack(vjust=0.5)) + 
  theme_void() + 
  theme(plot.title = element_text(size = 30, face = "bold"))

Mortality Rate among Genders

patient_gender <- patient
patient_gender_d = patient_gender[!is.na(patient_gender$deceased_date),]

patient_gender <- patient_gender %>%
  select(sex) %>%
  na.omit() %>%
  group_by(sex) %>%
  summarise(patient_num = n())

patient_gender_d <- patient_gender_d %>%
  select(sex) %>%
  na.omit() %>%
  group_by(sex) %>%
  summarise(patient_num = n())

patient_gender_d[2] = patient_gender_d[2]/ patient_gender[2] * 100

ggplot(patient_gender_d, aes(x = sex, y = patient_num, fill = sex)) +
  geom_bar(stat="identity") +
  xlab("mortality rate") +
  ylab("Gender") +
  ggtitle(label = "Mortality Rate by Gender")

# Filter out empty value for confirmed date
time_data <- time
# Plot confirmed cases for each day
ggplot () + 
  geom_point(data = time_data, aes(x = as.Date(date, format = "%Y-%m-%d"), y = confirmed), color = "blue") +
  geom_point(data = time_data, aes(x = as.Date(date, format = "%Y-%m-%d"), y = deceased), color = "red") + 
  geom_point(data = time_data, aes(x = as.Date(date, format = "%Y-%m-%d"), y = released), color = "green") +
  scale_x_date(date_labels = "%b %d", date_breaks = "30 days")

Confirmed Cases: Age Group vs. Province

patient_age_province <- patient_1
patient_age_province$age = 2020 - patient_1$birth_year
patient_age_province$age_group = cut(patient_age_province$age,
                        breaks = seq(0,90, by=10),
                        right = FALSE,
                        labels = c("0-10","10-20","20-30",
                                   "30-40","40-50","50-60",
                                   "60-70","70-80","80-90"))

patient_age_province %>%
    select(age_group, province) %>%
    na.omit() %>%
    group_by(age_group, province) %>%
    summarise(Count = n()) %>%
    ggplot() +
    geom_tile(aes(x = age_group, y = province, fill = Count)) +
    geom_vline(xintercept = seq(0.5,9.5,by = 1), linetype = 'dashed') +
    geom_hline(yintercept = seq(0.5,14.5,by = 1), linetype = 'dashed') +
    scale_fill_gradientn(colours = c("green","red"),
                         values = c(0,0.1,1)) +
    scale_x_discrete(expand = c(0,0)) +
    scale_y_discrete(expand = c(0,0)) +
    theme_classic() +
    theme(text = element_text(size = 15, face = "bold"),
          axis.text.x = element_text(angle = 90),
          legend.position = "top",
          legend.key.width = unit(3,"cm"))

Confirmed Cases: Age Group vs. Province vs. Gender

patient_age_province_gender <- patient_age_province
patient_age_province_gender %>%
    select(sex, age_group, province) %>%
    na.omit() %>%
    group_by(sex, age_group, province) %>%
    summarise(Count = n()) %>%
    ggplot() +
    geom_tile(aes(x = age_group, y = province, fill = Count)) +
    geom_vline(xintercept = seq(0.5,9.5,by = 1), linetype = 'dashed') +
    geom_hline(yintercept = seq(0.5,14.5,by = 1), linetype = 'dashed') +
    scale_fill_gradientn(colours = c("green","red"),
                         values = c(0,0.1,1)) +
    scale_x_discrete(expand = c(0,0)) +
    scale_y_discrete(expand = c(0,0)) +
    theme_classic() +
    theme(text = element_text(size = 15, face = "bold"),
          axis.text.x = element_text(angle = 90),
          legend.position = "top",
          legend.key.width = unit(3,"cm"))   +
    facet_wrap(~sex)

Visualize Confirmed Cases on a Map

case$longitude <- as.numeric(as.character(case$longitude))
## Warning: NAs introduced by coercion
case$latitude <- as.numeric(as.character(case$latitude))
## Warning: NAs introduced by coercion
# Set Google API key
register_google(key = "AIzaSyCiHpBw6DsGxXs6pgfgQTd2tP4wAvzrmJI")
# Get Map from Google Maps API
map = get_googlemap(center = c(lon = 127.7669, lat = 35.9087),
                    zoom = 7, scale = 4,
                    maptype = 'roadmap',
                    color = 'color')

figure <- ggmap(map) +
    theme_void() +
    ggtitle("COVID-19 Cases in South Korea") +
    scale_color_gradientn(colors = rainbow(5)) +
    theme(plot.title = element_text(color = "blue"),
          panel.border = element_rect(color = "grey", fill = NA, size = 2))

figure + geom_point(data = case, 
                    aes(longitude, latitude, size= confirmed, 
                        color=confirmed, group=confirmed))
## Warning: Removed 109 rows containing missing values (geom_point).

Confirmed Cases Over Time Animation

# Get a data frame that contains both time and coordinates
case_bak <- subset(case, select = c(province, longitude, latitude))

geo_time <- merge(case_bak, timeprovince, by="province")
geo_time$date <- as.Date(geo_time$date, format = "%Y-%m-%d")


# Set Google API key
register_google(key = "AIzaSyCiHpBw6DsGxXs6pgfgQTd2tP4wAvzrmJI")
# Get Map from Google Maps API
map = get_googlemap(center = c(lon = 127.7669, lat = 35.9087),
                    zoom = 7, scale = 4,
                    maptype = 'roadmap',
                    color = 'color')

figure <- ggmap(map) +
    theme_void() +
    ggtitle("COVID-19 Cases in South Korea") +
    scale_color_gradientn(colors = rainbow(5)) +
    theme(plot.title = element_text(color = "blue"),
          panel.border = element_rect(color = "grey", fill = NA, size = 2))

figure + geom_point(data = geo_time, 
                    aes(longitude, latitude, size= confirmed, 
                        color=confirmed, group=confirmed)) +
  transition_time(date)

### Confirmed Case Trajectory Visualization

# Set Google API key
register_google(key = "AIzaSyCiHpBw6DsGxXs6pgfgQTd2tP4wAvzrmJI")
# Get Map from Google Maps API
map = get_googlemap(center = c(lon = 127.7669, lat = 35.9087),
                    zoom = 7, scale = 4,
                    maptype = 'roadmap',
                    color = 'color')

ggmap(map) +
  geom_point(data = route,
             aes(x = longitude, y = latitude,col =  as.factor(global_id)), size = 5) +
  geom_line(data = route,
            aes(x = longitude, y = latitude,col =  as.factor(global_id), group = as.factor(global_id)), 
            size = 2,alpha = 0.7) +
  guides(col = FALSE) +
  theme(text = element_text(size = 15, face = "bold"))
## Warning: Removed 1954 rows containing missing values (geom_point).
## Warning: Removed 1954 row(s) containing missing values (geom_path).

Massive Infection Visualization

# Known Group Infection Events
group_infec <- tibble(lon = c(127.0518049,126.9165592,127.1217472,128.7368285,129.0771404,128.4941047,128.5707814,128.5665743,128.9099632),
                          lat = c(37.2367708,37.6338843,37.3881528,35.6486172,35.2159947,36.0579173,35.8507155,35.8397168,36.9273528),
                          address = c('650-103 mangpo-dong, yeongtong-gu, suwon, gyeonggi-do, south korea','1021 tongil-ro, jingwan-dong, eunpyeong-gu, seoul, south korea','20 seohyeon-ro 180(baekpalsip)beo, seohyeon-dong, bundang-gu, seongnam-si, gyeonggi-do, south korea','100-1 beomgok-ri, hwayang-eup, cheongdo, gyeongsangbuk-do, south korea','436-8 oncheon 1(il)-dong, dongnae-gu, busan, south korea','918 yuhak-ro, gasan-myeon, chilgok-gun, gyeongsangbuk-do, south korea','72-10 seongdang-dong, dalseo-gu, daegu, south korea','81 daemyeong-ro, daemyeong 10(sip)-dong, nam-gu, daegu, south korea','916 soro-ri, chunyang-myeon, bonghwa-gun, gyeongsangbuk-do, south korea'),
                          korean_name = c('수원 생명샘교회','은평 성모병원','분당 제생병원','청도 대남병원','부산 온천교회','칠곡 밀알 사랑의집','대구 한마음아파트','대구 신천지 교회','봉화 푸른 요양원'),
                          english_name = c('Soowon Saengmyungsame Church','Eunpyung Sungmo Hospital','Boondang Jesaeng Hospital','Chungdo Daenam Hospital','Busan Onchun Church','Chilgok Milal Sarang House','Daegu Hanmaeum Apartment','Daegu Sinchunji Church','Bonghwa Pureun Clinic'),
                          n_of_infections= c(10,14,11,118,34,22,46,4482,51))

# Pre-processing
group_infec_2 <- group_infec %>% select(lon,lat,korean_name,english_name,n_of_infections) %>% 
  rename(latitude2 = lat, longitude2 = lon, id = english_name) %>% 
  as.data.table() 

group_infec_3 <- group_infec_2[, list(label=HTML(
  paste(sep = "<br>",
        paste("G.I(eng): ", id),
        paste("G.I(kor): ", korean_name),
        paste("Num of infects:", n_of_infections)))),
  list(id, longitude2, latitude2)]

#Combining route and patient and pre-processing

agg_1 <- route %>% left_join(patient_1, by="global_id") %>% 
  mutate(infected_by = ifelse(is.na(infected_by),"Unk",infected_by)) %>% 
  as.data.table

agg_2 <- agg_1[, list(label=HTML(
  paste(sep="<br>",
        paste("Patient Id :", global_id),
        paste("Sex :", sex),
        paste("Country :", country),
        paste("Disease :", disease),
        paste("Group:", group),
        paste("Infection_reason:", infection_reason),
        paste("Infection_order:",  infection_order),
        paste("Infected_by:", infected_by),
        paste("Contact_number:", contact_number),
        paste("Confirmed_date:", confirmed_date),
        paste("State:", state)))), 
  list(global_id, longitude, latitude)]

listed <- list(agg_2, group_infec_3)
agg_3 <- rbindlist(listed, use.names = TRUE, fill = TRUE)

m = agg_3 %>% 
  leaflet() %>%
  setView(128.5, 36.5, zoom = 7) %>%
  addTiles() %>%
  addProviderTiles("CartoDB.Positron") %>%
  #addProviderTiles : Stamen.Toner, CartoDB.Positron, Esri.NatGeoWorldMap, MtbMap
  addCircleMarkers(
    lat =  ~ latitude,
    lng =  ~ longitude,
    label = ~label,
    clusterOptions = markerClusterOptions(),
    labelOptions = labelOptions(noHide = F, 
                                direction = "left",
                                style = list(
                                  "color" = "black",
                                  "box-shadow" = "4px 4px rgba(0,0,0,0.25)",
                                  "font-size" = "13px",
                                  "border-color" = "rgba(0.5,3,0.5,0.5)"))) %>% 
  
  #Addding group infections
  addMarkers(
    lat =  ~ latitude2,
    lng =  ~ longitude2,
    label = ~label,
    labelOptions = labelOptions(noHide = F, 
                                direction = "right",
                                style = list(
                                  "color" = "red",
                                  "font-size" = "13px")))
## Warning in validateCoords(lng, lat, funcName): Data contains 338 rows with
## either missing or invalid lat/lon values and will be ignored
## Warning in validateCoords(lng, lat, funcName): Data contains 2050 rows with
## either missing or invalid lat/lon values and will be ignored
saveWidget(m, file="mass.html")

Regression Analysis